The closure of the Strait of Hormuz offers another stark reminder of the potential for concentrated supply chains to trigger cascading global crises. Despite repeated disruptions, governments have made little progress in mapping these vulnerabilities, leaving major economies dangerously unprepared for future shocks.

CAMBRIDGE—The closure of the Strait of Hormuz is just the latest in a series of major supply shocks the global economy has experienced since 2020. Yet each time, the resulting shortages appear to catch policymakers off guard. From personal protective equipment at the start of the COVID-19 pandemic to fertilizer and sulfur today, the key chokepoints and complex supply-chain interdependencies that cause these shortages remain poorly understood, often becoming visible only once crises are already underway.